JPH0410004A - Numerical controller - Google Patents

Abstract

PURPOSE:To instruct the data for decision of the upper limit feeding speed and an allowable machining error and to shorten the machining time by providing a decoder which reads the commanding value of the allowable machining error or the allowable acceleration out of the NC data and an allowable value corrector which corrects these machining error and acceleration. CONSTITUTION:A decoder 2 reads the correction commanding value of the allowable machining error or the allowable acceleration out of the NC data. An allowable value corrector 4 corrects those machining error or acceleration. Thus the correction commanding value instructed to the NC data is read by the decoder 2, and the allowable machining error or the allowable acceleration are corrected by the corrector 4. Thus, the upper limit feeding speed and the allowable machining error can be changed. Then the rough machining time is shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a numerical control device, particularly to high-speed, high-precision machining.

[Prior Art] FIG. 3 is a block diagram showing the configuration of a feed rate (VoM) generator in a conventional numerical control device disclosed in, for example, Japanese Patent Laid-Open No. 58-35607. In the figure, (1)
reads a paper tape T with NC data perforatedN
C tape reader, and (2) is an NC tape reader (1
) connected to the NC data decoder. (5) is a clamp speed generator, and (6) is a comparison selection circuit.

Next, the operation will be explained.

Here, the paper tape T includes, for example, G O2x 100. It is assumed that NC data such as OR50, 0F 1000; is punched.

The NC data decoder (2) reads this data via the NC tape reader (1), and the above NC data is
: Clockwise circular arc, R50, 0: Radius (r) = 5 (1m
m, F 1000: Commanded feed speed (V,) -100
Decipher that it is 0 mm/min.

A clamp speed generator (5) calculates a clamp speed (Vo) based on the radius (r), which is one of the outputs of the NC data decoder (2), and a preset allowable machining error (ET).

A comparison and selection circuit (8) compares the output (Vo) of the clamp speed generator (5) with the command feed speed (Vi) and outputs the smaller one as the actual feed speed (vcM).

It is well known that in a system that performs exponential acceleration/deceleration after interpolation, the radius error (Δr) when circular interpolation is performed is expressed by the following equation (1). Here, T is the acceleration/deceleration time constant, and T is s
p is the servo position loop time constant.

Therefore, when calculating in the clamp speed generator (5), V in equation (1) is replaced by V in equation (2). By substituting M, we get ΔrllllIET.

Since the selection of VcM≦Vc is made by the comparison and selection circuit (6), Δr≦ET always holds true in this system, and the cutting accuracy can be kept below ET.

[Problems to be Solved by the Invention] Generally, cutting processes include rough cutting and finishing stages, and during rough cutting, short machining time is more important than machining accuracy. Therefore, the allowable machining error (ET) should be set large when rough cutting, but since the error during arc cutting occurs only in the direction where the machining radius becomes smaller, E when cutting outside the circular arc is the finishing allowance. If it is larger, there is a possibility that it will cut into the product part. Therefore, ET must be set sufficiently smaller than the finishing allowance, which poses a problem that the roughing machining time becomes longer.

Furthermore, Japanese Patent Application Laid-Open No. 61-279389 discloses a technique for reducing the machining speed of a circular arc portion in laser processing to a speed below the predicted circular arc error, but this publication also differs from the above-mentioned conventional technique. Similarly, the amount of error (Δr)
There was a problem in that there was no equivalent definition for the method of specifying , and it was not possible to set it arbitrarily according to the machining shape, etc.

This invention was made in order to solve the above-mentioned problems, and aims to provide a numerical control device that can shorten the rough machining time by allowing commands such as allowable machining errors using NC data. purpose.

[Means for Solving the Problems] A numerical control device according to the present invention includes a decoder that reads an allowable machining error or an allowable machining speed from NC data.

Further, the numerical control device according to the present invention includes a decoder that reads a correction command value of allowable machining error or allowable acceleration from NC data, and a allowable value corrector that corrects the allowable machining error or allowable acceleration based on the correction command value. It is equipped with the following.

[Function] In this invention, the allowable machining error or allowable machining speed commanded by NC data is read by an NC data decoder, and the upper limit feed speed and allowable machining error are changed based on these command values. I can do it.

In addition, in this invention, the correction command value instructed in the NC data is read by the NC data decoder, and the permissible machining error or permissible acceleration is corrected by the permissible value corrector. can be changed.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a feed speed (vcM) generating section in a numerical control device according to an embodiment of the present invention. In the figure, (1) is an NC table reader that reads a paper tape T on which NC data is perforated, and (2)
) is an NC data decoder connected to the NC tape league (1). (3) is a buffer register that holds a correction command value, (4) is a tolerance value corrector, (5) is a clamp speed generator, and (6) is a comparison selection circuit.

For example, the paper tape T has G 61.1 P 80.

G O2x 100. It is assumed that NC data such as OR50, 0F 1000; is punched.

The NC data decoder (2) reads this data via the NC tape reader (1) and calculates P2O: correction command value (P) -
60%, G O2: Clockwise circular arc, R50,0: Radius (
r) = 50mm, F 1000: Commanded feed speed (vl
)=1000mm/min.

The buffer register (3) inputs and stores the correction command value (P) - 60% of the above NC data.The tolerance corrector (4) inputs and stores the correction command value (P) and the allowable machining error ( E,
) is read out, and, for example, the effective allowable machining error (e,) is calculated using the following equation and (e,) is output.

oo-P ° Bi” 100 Clamp speed generator (5) is r and effective allowable machining error e
The clamp speed (Vo) is calculated based on, for example, the following equation.

Then, V in equation (3) is added to V in equation (1). Substitute 0M By doing so, Δr−eT becomes.

The comparison and selection circuit (6) outputs the smaller of Vc and vl as V. Therefore, from 0M where VCM≦Vc, Δr-eT always holds true in this system.

In addition, in the above embodiment, the tolerance corrector (4) generates the effective allowable machining error (eT) based on the allowable machining error (E, ).
and a clamping speed generator (Vo) that calculates the clamping speed (Vo) based on the radius (r) and the effective allowable machining error (e).
5), but the same effect can be obtained by using the known fact that the machining error of a circular arc is approximately proportional to the centroidal acceleration and using the allowable machining speed (80) as a standard. An example of this is shown in FIG.

Next, its operation will be explained. Buffer register (3
) are the same. The permissible value corrector (4) reads the corrected command value (P) and permissible acceleration (AT), calculates, for example, the effective permissible acceleration 0O-P a T'″AT' 100 and outputs a.

A clamp speed generator (5) calculates a clamp speed (Vo) based on r and al. For example, if V −f "T 〒, then by substituting ■ into V.M in equation (1), the following is obtained.

The comparison and selection circuit (6) outputs the smaller of V and Vl as ■. Therefore, from 0M where ■oM≦■o, in this system, −aT always holds true for Δr≦.

In the above embodiment, the correction command value (P) is stored in the buffer register (3), but it may be directly input to the allowable corrector (4).

In addition, although the calculation of the tolerance corrector (4) is set to a T - A r X, the input includes the correction command value (P) and the output is e
Alternatively, any calculation may be used as long as aT. For example, if you calculate e T-P or aT-P, N
Allowable errors can be commanded directly with C data.

Therefore, in such a case, the buffer register (3) and the tolerance corrector (4) are used in the embodiments of FIGS. 1 and 2.
) may be omitted, and the correction command value (P) decoded by the NC data decoder (2) may be output directly to the clamp speed generator (5) as the tolerance (eT) or (al).

[Effects of the Invention] As described above, according to the present invention, data for determining the upper limit feed rate and allowable machining error can be commanded using NC data, so machining time can be shortened while ensuring accuracy. This effect has been obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a numerical control device according to an embodiment of the present invention, FIG. 2 is a block diagram of a numerical control device according to another embodiment of the present invention, and FIG. 3 is a block diagram of a conventional numerical control device. It is a diagram. In the figure, (1) is an NC tape reader, and (2) is an NC tape reader.
A data decoder, (3) a buffer register, (4) a tolerance corrector, (5) a clamp speed generator, and (6) a comparison selection circuit. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (2)

[Claims] (1) The upper limit feed rate is determined based on the shape of the workpiece and the allowable machining error or allowable acceleration, and even if a feed rate exceeding the upper limit feed rate is commanded, the actual feed rate is set to the upper limit feed rate. A numerical control device for clamping, comprising: a decoder that reads the command value of the allowable machining error or the allowable acceleration from NC data. (2) The upper limit feed rate is determined based on the shape of the workpiece and the allowable machining error or allowable acceleration, and even if a feed rate exceeding the upper limit feed rate is commanded, the actual feed rate is set to the upper limit feed rate. In the numerical control device for clamping, the correction command value of the allowable machining error or the allowable acceleration is set to N.
1. A numerical control device comprising: a decoder that reads from the C data; and an allowable value corrector that corrects allowable machining error or allowable acceleration based on the correction command value.